1. Technical Field of the Invention
The present invention relates to a method and system for prioritizing services execution in a telecommunications switch and in particular for providing customized prioritization of services to be executed in an intelligent network in response to a telecommunications event.
2. Description of Related Art
As stored program-controlled (SPC) switching systems have evolved, a wide variety of useful features have been developed to extend the communication capabilities such systems provide. Such services or features include call forwarding, xe2x80x9c800xe2x80x9d or toll free services, call screening, and the like. With the development and improvement of sophisticated telecommunications applications, the telecommunications industry has adopted the term xe2x80x9cintelligent networkxe2x80x9d (IN) to denote a concept and architecture for providing vendor-independent and network-independent interfaces between the service logic and the transmission and switching system of a multi-enterprise telecommunications network. The goals of the IN are to centralize the service execution in a control node within a telecommunications network in order to provide rapid definition, testing and introduction of new services as well as the modification of existing services. IN also provides greater flexibility in the design and development of new services in a multi-vendor environment with shorter lead time, and standard network interfaces. The basic concept behind IN is to move the xe2x80x9cintelligencexe2x80x9d out of each local exchange or Service Switching Point (SSP) and centralize the services providing the intelligence in a Service Control Point (SCP).
During the processing and execution of a call in an IN telecommunications system, including call set-up, call duration, and call termination, the SSP occasionally determines whether certain trigger conditions are met. These trigger conditions, for instance, might include the receipt of an abbreviated dialing code or the receipt of an indication that a called station is currently busy. If no trigger conditions are met, then the SSP proceeds according to normal call processing. Otherwise, if certain trigger conditions are met, the SSP sends a query over a Signaling System No. 7 (SS7) network to the SCP or to a home location register (HLR) requesting instructions on how to proceed with processing of the call.
To handle these requests for instructions, the SCP includes a service interaction manager (SIM) that is programmed to respond to each possible trigger condition by executing certain services according to a particular hierarchy or sequence. Once the services are performed in accordance with the particular services hierarchy, an instruction or set of instructions are sent from the SCP to the SSP informing the SSP on how to proceed. The ongoing call is further processed by the SSP according to these instructions.
Despite efforts to permit more rapid implementation of services through use of the IN, significant portions of the processing software in the SCP must be replaced when adding new services. This is because, in current systems, the SIM is specifically aware of which services are available in a service library of the SCP. In other words, the identity of the available services is hard coded into the SIM. Each time new services are introduced into the service library, the SIM logic must be upgraded so that it is aware of the new services.
In addition, the SIM logic is programmed to execute the applicable services in a fixed sequence in response to a certain trigger condition. Under this system, the hierarchy of services cannot be customized. Moreover, if a new service that is implicated by a certain trigger condition is added, the SIM logic must also be reprogrammed to include a new fixed sequence that includes the new service. The static tightly coupled system formed between the SIM and the service library further prevents the removal of a service from the library (e.g., to perform maintenance or fix a programming defect) without modifying the SIM logic to account for the removed service because the SCP is not programmed to account for a temporary or permanent absence of a service from the library.
Because of these characteristics in current systems, the introduction of new services in an IN network requires an upgrade in the SIM associated with each SCP in the system. Similarly, the removal of a service, even if only temporarily, requires a modification of the SIM logic. Essentially, this means that the addition of new services or the removal of a service requires a corresponding replacement of the SIM. Such replacements are costly in terms of the development time for the SIM logic as well as in terms of the time and effort required to replace the SIM in all of the SCP nodes of the network. The effort and expense associated with these upgrades tends to delay the implementation of new services in IN networks.
There is a need, therefore, for a method and system to help reduce the cost associated with implementing new services and to permit more rapid introduction and implementation of new services in an IN network. There is also a need for a method and system for identifying the currently available services and for customizing the sequence in which the applicable available services are executed in response to a certain trigger point.
The present invention comprises a dynamic method and system for the generation and execution of a sequence of services in response to a trigger condition in an intelligent network (IN). Upon detection of a trigger condition in a service switching point (SSP), a service interaction manager (SIM) in a service control point (SCP) is notified of the trigger. The SIM determines which services are implicated by the particular trigger condition (i.e., which services might need to be executed in response to the trigger condition). This determination is made by referring to a SIM memory, which contains an overall framework of the allowable service sequences, thereby ensuring that any sequences that can cause problems in the network are not permitted.
The SIM also retrieves subscription information relating to a particular telecommunications subscriber from the subscriber""s home location register (HLR). This subscription information may contain certain priority preferences that the subscriber has with respect to the order of service execution for responding to various trigger conditions. In addition, the SIM determines which of the implicated services are currently available in a service library of the SCP by querying the service library. For each of the implicated and available services, a service logic program (SLP) and a set of sequencing data that give context to the service relative to other services, are also retrieved.
By determining which services the subscriber subscribes to and which services are currently available in the service library, the list of implicated services is reduced to an applicable set of services. Then, using the sequencing data from the service library and the priority preferences from the HLR, the applicable services are assembled into a customized sequence for execution. At least one service is then executed in accordance with the adjusted sequence. Next, at least one service is executed in accordance with the customized sequence
As a further enhancement, the present invention may compare the customized sequence for service execution with a set of mandatory sequencing rules stored in the SCP. If necessary, the customized sequence can be adjusted to comply with these rules. A message is then sent to the SSP providing instructions for further processing of the call connection.
In accordance with the invention, service modules can be added or removed from the service library without having to modify or replace the SIM logic. The SIM detects the presence or absence of services in the service library and generates the sequence for executing services accordingly. In addition, the service priority data stored in the service library and the HLR can be customized according to a particular subscriber""s or network operator""s preferences or needs. This preference data, in turn, allows sequences for executing services to be customized. Preferably, in accordance with the invention, the SLP comprises JAVA code or some other interpretive language so as to simplify the dynamic sequencing process and to facilitate reflection (i.e., the ability to discover and process information about the SLP without having to makes changes to the SIM logic).